How long until Europe builds a Google?

As London's first Technology Week nears its end, there's been a lot of discussion about how Europe's digital hubs are gearing up to take on Silicon Valley. But despite all the talk, the region has yet to spawn its very own tech giant, along the lines of Google, Facebook or Twitter.

These tech success stories are known on the start-up scene as "unicorns" – and Europe is more adept at creating them than many think, according to boutique investment bank GP Bullhound.

It published a report earlier this week highlighting that Europe has produced 30 technology companies worth $1 billion or more between January 2000 and April 2014, with the average valuation around $3 billion.

"We are developing angel networks but they aren't as big or sophisticated as the U.S. And it's very difficult to get capital out of banks," he said. "The financing of expansion is actually quite tricky in the U.K., although we are trying to overcome that."

The problem is Europe-wide, according to Pawel Chudzinski, co-founder of Point Nine Capital, a Berlin-based angel venture capital firm.

"Europe is underfinanced in the tech space. At every stage, there's just not enough money, especially by U.S. standards," he told CNBC.

One reason for this, according to Chudzinski, is that high-risk tech investment didn't take off in Europe until the 1990s –substantially later than in the States.

"Then the dot-com bubble burst and tech investing became a big no-no," he said. "It means investors haven't had the chance to reap big financial rewards from investing in European tech, and this puts them off."

European start-ups are between five and ten times less funded than their North American counterparts, according to Eze Vidra, head of Google's start-up hub, Campus London, although he argued the investment picture was improving.

This is in part due to the popularity of equity crowdfunding in Europe, he said, and also the introduction of tax breaks for "angel investors".

"I believe we're at the beginning of something amazing," Vidra added. "We're going to see more and more European start-upsgrowing to become billion-dollar businesses."

Snapped up

But although early-stage funding might be powering ahead, it's sustaining the growth that is the real issue, according to Cable. He said there was a substantial gap between raising early-stage finance – "from family, fools and friends" – and later-stage investment.

As a result, most British companies have had to look to the U.S.' West Coast for later-stage funding, according to Peter Briffett, the COO of event planning app YPlan. Last year, YPlan announced a $12 million funding round led by U.S. venture capital firm Catalyst Partners.

"But things are changing. Ultimately I think there are investors here that are willing to take it to the next round levels," he told CNBC.

The risk if investors don't step up is that Europe'ssuccessful companies get snapped up by U.S. companies.

"We see far too many good British companies being swallowed up by M&A activity when it would be better for the country if they kept growing," Cable warned.

Culture clash?

What is also not in European companies' DNA is self-promotion – or that's at least according to London Mayor Boris Johnson. Speaking at the launch of London Technology Week on Monday, Johnson said "a British diffidence about making billions of pounds" could be one reason why the country had not yet produced a tech giant.

And Cable concurred. "We don't have here the American, slightly over-the-top style – that's not very British," he said, although he stressed that diversity across the start-up scene, with a growing number of immigrant entrepreneurs, meant things were changing.

So with most industry-watchers agreeing that progress wasbeing made across Europe's tech scene, how long will it be before a tech giant – or "the next Google" - is born?

"You're talking within three or four years, certainly on growth rate alone, you'll start to see some companies really taking that mantle up," YPlan's Briffett said.

But perhaps there is too much focus on Europe creating a Google, Facebook or Twitter. "These are super-mega unicorns, and they only come around every ten years," Chudzinski added. "There's no proper reason Europe hasn't produced one yet – just give it time."